Logic gates created from DNA and bacteria could form basis of biological computers

The design of an "AND gate" created by Imperial College London scientists using E-Coli bacteria and DNA that could form the building blocks of a new generation of microscopic biological computers

DNA is often referred to as the building block of life. Now scientists from Imperial College London have demonstrated that DNA (and bacteria) can be used to create the fundamental building blocks of a computer - logic gates. Using DNA and harmless gut bacteria, the scientists have built what they claim are the most advanced biological logic gates ever created by scientists. The research could lead to the development of a new generation of microscopic biological computing devices that, amongst other things, could travel around the body cleaning arteries and destroying cancers.

While previous research had already proven biological logic gates could be made, the Imperial College scientists say the big advantage of their creations is that they behave like their electronic counterparts - replicating the way that electronic logic gates process information by either switching "on" or "off." Importantly, the new biological logic gates are also modular, meaning they could be fitted together to make different types of logic gates and more complex biological processors.

To create a type of logic gate called an "AND gate," the team used modified DNA to reprogram Escherichia Coli (E.Coli) bacteria to perform the same switching on and off process as its electronic equivalent when stimulated by chemicals. In a similar way to the way electronic components are made, the team demonstrated that the biological gates could be connected together to form more complex components.

The team also created a "NOT gate" and combined it with the AND gate to produce the more complex "NAND gate." NAND gates are significant because any Boolean function (AND, OR, NOT, XOR, XNOR), which play a basic role in the design of computer chips, can be implemented by using a combination of NAND gates.

The researchers will now try and develop more complex circuitry that comprises multiple logic gates. To accomplish this they will need to find a way to link multiple biological logic gates together that is similar to the way in which electronic logic gates are linked together to enable complex processing to be carried out.

"We believe that the next stage of our research could lead to a totally new type of circuitry for processing information," said Professor Martin Buck from the Department of Life Sciences at Imperial College London. "In the future, we may see complex biological circuitry processing information using chemicals, much in the same way that our body uses them to process and store information."

The team also suggests that these biological logic gates could one day form the building blocks of microscopic biological devices, such as sensors that swim inside arteries, detecting the build up of harmful plaque and rapidly delivering medications to the affected area. Other sensors could detect and destroy cancer cells inside the body, while others could be deployed in the environment to monitor pollution and detect and neutralize dangerous toxins.